This application relates to oligonucleotide primers and nucleic acid probes that are useful for amplification and/or detection of human inhibitor of DNA-binding (Id) genetic sequences, and in particular for selective amplification and/or detection of human Id1, Id2 and Id3.
Inhibitor of DNA-binding (Id) proteins are transcription factors and are members of a subfamily of Helix-Loop-Helix (HLH) proteins. These proteins contain a motif that consists of two segments capable of forming amphipathic alpha helices connected by a nonconserved loop. Other members of the HLH family (basic HLH, or bHLH proteins) also contain a basic region just to the amino terminal side of this motif that consists of two to three clusters of basic amino acid residues. Various proteins containing the bHLH motif can form homodimeric and heterodimeric complexes with other bHLH proteins and it is through the basic region that these complexes bind to the target DNA (Murre et al., Cell, 1989, 56, 777-783; Murre et al., Cell, 1989, 58, 537-544). The Id proteins containing the helix-loop-helix domain, but are lacking the basic region. These Id proteins are still able to form heterodimers with other bHLH transcription factors affecting transcription, but they lack DNA-binding ability and are therefore negative regulators of the bHLH transcription factors.
Four members of the Id family have been identified in mammals and the first, Inhibitor of DNA binding-1 (Id-1), originally isolated in the mouse, has been shown to exist in two forms in the human as a result of alternative splicing (Benezra et al., Cell, 1990, 61, 49-59; Deed et al., Biochim. Biophys. Acta., 1994, 1219, 160-162; Hara et al., J. Biol. Chem., 1994, 269, 2139-2145; Nehlin et al., Biochem. Biophys. Res. Commun., 1997, 231, 628-634; Zhu et al., Brain Res. Mol. Brain Res., 1995, 30, 312-326).